Can with quick-opening lap seam



- May 11, 1965 O. F. ECKLUND ETAL CAN WITH QUICK-OPENING LAP SEAN med Dec. 1o, 1963 3Ll// m T|||||||LAHH:| 1MMHM l Z f f WM n 1 il d. f7 -w -Ve y Arroz/viva 3,182,891 CAN WITH QUICK-OPENING LAP SEAM Oscar Frederick Ecklund, Barrington, lll., and Arnold Robert Rein, Menasha, Wis., assignors to American Can Company, New York, N.Y., a corporation of New Jersey Filed Dec. 10,- 1963Ser. No. 329,442 7 Claims. (Cl. 229-51) The present invention relates to a tubular container body made principally of bre and having a pull tabl along the side seam to open the container. The invention has particular reference to an improved lap side seam construction which provides the inner edge portion of the seam with a moisture barrier and permits a clean opening ofthe seam without delamination of the fibrous material in the container body.

Certain products such as biscuit dough and the like are packaged in containers comprising a tubular fibre body usually with metal end closures permanently secured thereto. The edge margins of thebody preferably are joined in an adhesively secured lap side seam with the outer lap extending beyond the seam to provide a pull tab lfor breaking the seam to open the container. Since products like biscuit dough contain a certain amount of. moisture in their packaged state, the inner edge of the side seam must be provided with a moisture barrier to prevent dehydration of the product and softening of the seam which otherwise may impair the seal. Y

In containers of this type, a strong adhesive bond at the side seam: is required to withstand considerable internal pressure developed by the product in storage. With such a strong bond, it has been'found when the tab is pulled outwardly to break open the seam, the bond holds to such an extent as to cause the outer skin of the fibre material to break away and delaminate in the form of thin tissue or onion skin." This "onionskin is of considerable annoyance to the consu-mer since it requires removal to fully open ythe container, is generally unsightly, and pieces could break loose and become stuck to the product.

A principal object, therefore, of the present invention is the provision of an improved seam construction for a seam opening container which is fully moisture-proof and permits of a clean breaking of the seam in the opening of 4the container.

Another object of this invention is the provision of a side seam construction in a bre body container which provides a protective barrier to moisture in the product and permits of quick, clean breaking of the seam without delamination of the body.

l Another object of this invention is the provision of a side-open can having a quick-opening side seam which is moisture resistant and limits any tearingor splitting of the can body material incidental to breaking the seam to Ythe bonded area of the seam itself.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, taken inv connection with the accompanying drawings, discloses a preferred embodiment thereof. v

With these objects in view, the present invention contemplates a tubular libre body with its marginal edges overlapped to provide the inner and outer laps of a lap seam, a moisture-proof liner hemmed over the inner lap margin to protect the seam against moisture penetration, a first adhesive strip securing all but the extreme edge of the hemmed liner to the outer side of the inner lap, and a second adhesive partially'olfset from the rst securing the outer lap to the hemmed liner out to the very edge of the hemmed liner.

Referring to the drawings:

FIG. 1 is a perspective view of a sealed container embodying the present invention.

FIG. 2 is a plan view of a body blank used in the com tainer of FIG. 1, with portions being broken away.

FIG. 3 is an enlarged sectional view taken substan-r tially along line 3-3 of FIG. 2.

FIG. 4 is an enlarged fragmentary sectional view of the side seam of the container taken substantially along line 4-4 of FIG. 1.

FIG. 5 is a view similar to FIG.` 4, showing the seam being broken to open the container.

As a preferred or exemplary embodiment of thevpres'- t ent invention, the drawings illustrate a composite container comprising a fibre body generally designated 10 having a side seam generally designated 11 extending longitudinally thereof, a pull tab 12 extending circurrpv ferentially from the seam, and top and bottom end elo-J sures 13, 13 of sheet metal or the like securedto the ends of the body.

Fibre body 10 preferably is made from a ilat blank' generally designated 14 (FIG. 2) which vis bent into tubo* lar shape with its opposite marginal'edgesvov'erlapp'ed to form the inner and outer laps lla and 11b, respectively,

of side seam 11. Blank 14 preferably comprisesa main fibre ply 16, a liner ply 17 of a moisture-proof, gasfproo and grease-proof material such as metallic foil (tin or aluminum) coextensively adhered to the surface of ibre.'vv ply 16 which forms the interior of the body, and a pro.-` tective film or coating 18 covering the :other vsurface 1 which forms the exterior of the container. Liner ply-17 preferably is backed with a thin paper or libre layer 19.

whichis disposed between the foil and iib're body ply .16.

Coating 18 may be a wax or organic resin material Slflii,

able `for externally protecting fibre ply 16, or may be ai metallic foil similar to liner lply 17 and applied inthe 4 and identfyform of a label with appropriate decorative ing indicia on its exterior surface.

One end margin of body blank 14 extends beyond they I point where the inner and outer laps register toprovidef pull tab 12 as the means for breaking the seam to open-the container. he top and bottom edges of the tab vare angu' give access to its contents.

Liner ply 17 and paper backing 19 extend beyond the end of fibre ply 16 opposite pull tab 12 and are reversely folded thereover (FIG. 3) to form a hem 23. This prof vides the necessary protection for the inner lap edge'of fibre ply 16 against moisture attack. from the product. The

extent of the reverse fold of hem 23 is selected to provide I a predetermined width for effecting the side seam seal to outer lap 11b. A stripe 24 of suitable adhesive secures hem 23 to the outer marginal surface of. innerlap ll'a` This adhesive stripe is less than the width-.0f hem 2,3 `and terminates short of a free edge 25 of the hem thereby permitting this edge to remain unsecured to the inner lap.

A second adhesive stripe 26 secures the outer surface of hem 23 to the inner surface of outer lap 11b (FIG, 4) v to complete the lap side seam 11. This latter adhesive may be of the same type as stripe 24 and is applied either directly over hem 23 or to the opposite end of blank 14 I at a position to properly register with the hem when the blank is folded into tubular shape. The adhesive stripe 26 may extend the full width of hem 23 out to its-free j edge 25; or it may terminate slightly short of the edge 25. It is essential only that the terminus of the stripe 26 Patented May-11,19.65 l

3 be disposed closer to the `hem edge 25 than the terminus of the stripe 24. As a practical matter, it is preferred that the terminus of the stripe 26 extend no further than the hem edge 25 so as to obviate any possibility of the pull tab 12 being bonded directly to the outside of the body 10.

As an example, the width of hem 23 may be Vs in. and is sealed for its full width to outer lap 11b by adhesive stripe 24, thereby leaving its free edge 25 unsecured to the inner lap for a distance of about A in. Thus, the adhesive stripes 24 and 26 along one edge are offset in such a manner as to create a preferential failing point to enable breaking the seam 11 without encountering onion skinning.

This seam construction is such that, when pull tab 12 is pulled back to break open side seam 11, the offset relationship of the adhesive stripes 24 and 26 cause all of the stress of opening to be localized on the hem 23 to the inside of its free edge 25. It is this offset relationship of the glue stripes that cause the stress to be localized in the hem 23; and it is not essential that glue stripe 26 actually coincides with the edge of hem 23. This causes delamination of the overlapped portion of thin fibre backing 19 within hem 23 as the weakest point of the seam, back to a point A corresponding to the edge of inner lap 11b, at which point liner ply 17 and backing layer 19 will sever in a clean, neat opening (FIG. Thus, a seam construction is provided comprising only two thicknesses of fibre body ply 16 and which, by reason of hem 23 and its manner of securement to the respective inner and outer laps of the seam, provides thorough interior moisture proofing and quick clean opening capability free of onion Skinning.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction, and arrangement of the parts and that changes may be made in the steps of the method described and their order of accomplishment without departing from the spirit and scope of the inof said inner lap to protectively cover said edge' and provide a sealing hem of predetermined width;

a first adhesive stripe securing said hem to the outer'v surface of said inner lap, said stripe being offset away from the free edge of said hem; and

a second adhesive stripe securing said outer lap to a predetermined width of said hem and terminating closer to said hem free edge than said first adhesive stripe. 2. The construction of claim l wherein said inner liner comprises a metallic foil ply.

3. The construction of claim 1 wherein said hem is a libre-backed metallic foil material.

4. The construction of claim 1 wherein said second adhesive stripe secures the entire width of said hem to said outer lap.

5. The construction of claim 1 wherein said outer lap extends beyond said seam to provide a pull tab as a means to break said seam and open said container.

6. A side-open can having top and bottom end closures secured to a tubular body, comprising:

a fibre body ply and an inner moisture-proof liner coextensively adhered to said body ply;

one margin of said liner being hemmed over a longitudinal margin of said body ply and secured to its outer marginal surface by a first adhesive stripe extending therealong;

said adhesive stripe being offset from the edge of said hemmed margin;

said margins of said body ply and liner forming the inner lap of a lap side seam in which their opposite margins form the outer lap;

said outer lap extending peripherally beyond said side seam to provide a pull tab to break said seam and open said container; said inner lap being adhesively secured to said outer lap by a second adhesive stripe; said second stripe being wider than the first adhesive stripe with its terminus disposed closer to said hemmed margin edge than the terminus of said first stripe to provide said seam with. a preferential point of failure during opening. 7. The container of claim 6 wherein said liner is a laminate of metallic foil with a fibre backing layer, said fibre layer being adhered to said main body ply.

No references cited.

THERON E. CONDON, Primary Examiner.

FRANKLIN T. GARRE'IT, Examiner. 

1. AN IMPROVED QUICK-OPENING SEAM CONSTRUCTION FOR A CONTAINER HAVING A TUBULAR BODY WITH A MOISTURE-PROOF INNER LINER ADHERED TO THE INTERIOR OF SAID BODY, THE OPPOSED MARGINAL EDGES OF SAID BODY BEING OVERLAPPED TO PROVIDE AN INNER LAP AND OUTER LAP FORMING SAID SEAM, TH IMPROVEMENT COMPRISING: AN EXTENSION OF SAID LINER REVERSELY FOLDED OVER THE EDGE OF SAID INNER LAP TO PROTECTIVELY COVER SAID EDGE AND PROVIDE A SEALING HEM OF PREDETERMINED WIDTH; A FIRST ADHESIVE STRIPE SECURING SAID HEM TO THE OUTER SURFACE OF SAID INNER LAP, SAID STRIP BEING OFFSET AWAY FROM THE FREE EDGE OF SAID HEM; AND A SECOND ADHESIVE STRIPE SECURING SAID OUTER LAP TO A PREDETERMINED WIDTH OF SAID HEM AND TERMINATING CLOSER TO SAID HEM FREE EDGE THAN SAID FIRST ADHESIVE STRIPE. 